Fly tool for generating spherical surfaces



Deco 2, 19475 R. LINN FLY TOOL FOR GENERATING SPHERICAL SURFACES FiledMarch 17, 1945 2 Sheets-Sheet l INVENTOR.

BY ig/20nd Z1)",

Dec.2, 1947. R. LINN 2,431,815

IN V EN TOR.

1 f brand 1/) BY "7 Patented Dec. 2, 1947 FLY TOOL FOR GENERATINGSPHERICAL SURFACES Raymond Linn, Detroit, Mich, assignor to Ex- Cell-OCorporation, Detroit, Mich., a corporation of Michigan Application March17, 1945, Serial No. 583,321

Claims. 1

The present invention pertains to metal cutting tools, the general aimbeing to provide a novel fly tool for generating a spherical surface.

More particularly it is an object to provide such a tool which isadapted for use in an ordinary machine tool such as a boring machine,drill press or lathe without special adaptation or alteration of themachine.

Ruggedness and simplicity of construction are also objectives.

Further objects and advantages of the invention will become apparent asthe following description proceeds, taken in connection with theaccompanying drawings, in which:

Figure 1 is a front elevation of a tool embodying the present invention,the tool being shown in position to operate upon the workpiece and aportion of the supporting shank for the tool being broken away.

Figs. 2 and 3 are longitudinal sectional views of the tool of Fig. 1showing the position of the same relative to the work and respectivelythe beginning and the end of the cutting operation.

Fig. 4 is a bottom plan View of the tool shown in Fig. 1.

Fig. 5 is a sectional view taken along the line 55 in Fig. 2.

While the invention is susceptible of various modifications andalternative constructions, I have shown in the drawings and will hereindescribe in detail the preferred embodiment, but it is to be understoodthat I do not thereby intend to limit the invention to the specific formdisclosed, but intend to cover all modifications and alternativeconstructions falling within the spirit and scope of the invention asexpressed in the appended claims.

Referring more particularly to the exemplary embodiment of the inventionillustrated in the drawings, the particular tool there showncomprises agenerally cylindrical housing It] having an axially extending bore l Itherein opening from its lower end. Projecting axially from the oppositeend is a shank I2 adapted to be secured in a suitable machine toolspindle (not shown) for bodily rotation of the tool structure as a wholeabout its longitudinal axis by the spindle.

Slidable axially within the housing bore II is a core or plug M of roundcross section. This plug is restrained against rotation relative to the-nusing lit by pin and slot connection with the latter, a pin I5 fixedin the plug l4 being positioned to project into a longitudinalv slot H3in the housing. Abutment of the pin against the substantially 2 ends ofthe slot also limits the axial travel of the plug relative to thehousing.

The lower or outer end portion of the plug I4 is bifurcated, beingslotted at I! (Fig. 5). Moreover, the bifurcated outer end of the plugI4 is enlarged to provide a pair of spaced jaws or arms Ma between whichis pivoted a yoke l8 carried by pivot pins l9 fixed to the arms I la.Mounted on the yoke l8 and projecting inwardly therefrom is a cutterpoint 20 (Figs. 2, 3 and 4).

By causing the yoke 18 to pivot about the axis AA passing through thepivot pins l9 while the tool structure as a whole is revolved about itslongitudinal axis, the cutter point 2D is caused to generate a sphericalcontour on the workpiece W presented to it. Reaction of the workpiece Wagainst the tool structure, as an incident to longitudinal feed of thelatter toward the work, is utilized in imparting the desired pivotal orswinging motion to the yoke 18. For that purpose a bridge 2| (Fig. 5) isfixed to the inner ends of the pins I9 and carries a ball 22 adapted toseat in a centered recess in the end of the work. At the beginning ofthe cutting operation the tool structure is brought into the position ofFig. 2 where the ball 22 contacts the work, further axial movement ofthe plug it being prevented by such abutment so that in the course ofsubsequent forward axial feed of the housing It! the latter slidesdownward over the plug H. to the position of Fig. 3.

In order to utilize the relative axial movement of the housing In andplug I l incident to abutment of the ball 22 against the work W forpivoting the yoke [8 about its axis AA a suitable gearing is provided.Thus, in the illustrated construction, a toothed sector I 8a, centeredabout the axis A-A is fashioned integrally with the yoke l8 exteriorlyof the latter and arranged to mesh with a pinion 23 located in the slotl! and journaled on a transverse pin 2:3. This pinion in turn mesheswith a second pinion 25 also located in the slot I! and journaled on apin 25. The latter pinion 25 meshes with a rack 21 fixed to the interiorof the housing to. Consequently, as the plug I4 is shoved upward withinthe housing I!) from the position of Fig. 2 to that of Fig. 3 the pinion25 rolls along the rack 21, thereby rotating the intermediate pinion 23which in turn osoillates the yoke IS. A compression spring 28 partiallyhoused within a bore 29 in the upper end of the plug it and interposedbetween the end wall of such bore and the end wall of the housing boreH, yieldably urges the plug it to its outthrust position shown in Fig.2.

The particular workpiece W illustrated is typical of the type of workwhich the disclosed tool is adapted to perform and is in this instance aportion of a steering knuckle such as is used in automobile steeringsystems. In shaping such a device it is requisite that it have machinedon its end portions shown a surface contoured .in the form of 'apor'tionof a sphere. "The centering recess (not shown) in its outer end whichreceives the ball 22 is so located that the axis A-A on the tool willpass through the :center of the portion of the workpiece on which it isdesired to generate the spherical contour.

The operation of the disclosedtodlwilljn-general, be clear from theforegoing. By way of brief recapitulation, it may be observed that thetool structure as a whole is shifted-taxiallyato approach the work untilthe ball 22 contacts the endof .the work W as shown in Fig. 2. At thetime of such contact, the plug 14 is outthrust from the housing by thespring 28 and the toolstructure'is rotating continuously about itslongitudinal axis. While such rotation continues, axial feed-ofthehousing iilis continued'at a'slow rate. Any furtheraxial movement ofthe plug 1'4 relative to the work is prevented by the abutment of theball -22-against the work so that the plug -is gradually forced axiallyinto the housing ID as the latter moves en'clwise toward the work. Inthe course of such entry of the plug Hi into the housing 16, the pinion25 rolls alongtherack-Z! so thatt-he-yoke -I 8 isrocked about itsaxisA-Ain timed-relation With'the axial feed of the housing If MOI'COVBI,the rotation of the housing tflis'normally-efiected in timed relationwithits axial feed. The'cutter point 28 thus rotatesbodily'aboutthelongitudinal axis of the work and tool structure and at"the same time is rocked through anarcuate path so that itgeneratesa'spherical surface on the work. At the completion of themachining operation it is necessary merelytobackthe toolholderaxiallyaway from the work in order to disengage the tool completely from theworkpiece.

From the foregoing, it .will be perceived that a single point or fiycutting tool has .been .pro- 4 vided which is adapted to generate aspherical surface on a workpiece rapidly and effectually.

Since such a fly cutting tool has asmall .cutting contact with thework,.only low.stresses are-set up. By rapid rotation of the tool thmachining process may be rapidly accomplished .inspite of the small.cutting contact. The disclosed .tool is vespecially'effective inmachining workpiecessuch .as the steeringknuckle shown which, because oftheir odd shape, 'make it vdifiicult :to rotate the work in contact with:a form zturning -=,tool.

I claim as my invention:

1. Afly'tool for generating external ispherical surf-aces comprising, incombination, a ifirstimemberadapted to be fixed to a machinespindle orthe like 'TfOI rotation .of the "same, :a second member slidableaxially-relative toithe :firs'taand :restrained with reference thereto,means restraining said 'plug'andhousing against relative rotation, meansfor fixing said housing to a machine tool spindle l0 or the lik forrotation of the housing about its longitudinal-axis, and means operablein response toirelative axial movement of said plug and housing forrocking said cutter support about its i pivotal axis.

3. Afiy ",tool forgenerating spherical surfaces comprising, incombination, a housing having a {longitudinal bore opening from one endthereof, an ,axial shank projecting from the opposite end of saidhousing for supporting the same on a rotatable spindle or the like forbodily rotation aboutthe axis of said housing, a plug slidable in said.bore and restrained against rotation relative to 'said'h'ousin'g,cutter point, a support for .saidip'oint pivoted in the outer end ofsaidplug to swing said :point inan arcuate path lying in aplane'para'lleling the axis of said plug, a spring yie'ldaloly urgingsaid-plug outwardly of saidbore, means on said plug engageable with aworkpiece zpresentedito its outer end for thrusting said plug inward ofsaid bore as said housing is shifted axiallyitoward the workpiece, andmeans including meshing toothed elements carried by said :hous'ing andplug for swinging said support about its pivot in timed relation withthe axial movement.of said plug-relative to said housing.

4. IA fly 'tool for generating spherical surfaces comprising, incombination, a housing having a longitudinal bore opening from one endthereof, an axial shank projecting from the opposite end .of saidhousing for supporting the same on a rotatable spindle or the like forbodily rotation about the axis of said housing, a plug slidable in saidbore and restrained against rotation relative :to said housing, saidplug having a bifurcated end portion projecting outwardly from saidhousing bore, a cutter point, a support for said point pivotedbetween'the legs of the bifurcated end .of said plug to swing about anaxis transverse to the'latter, a spring-yieldably urging said .plugoutwardly of said bore, a bridge spanning thelegs of said bifurcatedends of said plug-and having :means thereon engageable with a Work-.piece presented to its outer end for thrusting said gplug inward ofsaid bore as said housing is advanced axially with respect to theworkpiece, a toothed sector rigid with said pivoted support, and meansincluding a pinion journaled onsaid plug and meshing with saidsector forswinging said support'about its pivot in timed relation with the .axialmovement of said plug relative to said .housing.

.5. A.fiy tool for generating spherical surfaces comprising, incombination, a first member adapted to be fixed toa machine spindle orthe likeifor rotation of the same, a second .member slidable axiallyrelative to the first and restrained against rotation with reference to.the same, a cutter support carried by said second member for bodilyrotation therewith and pivoted thereon to rock about an axis transverseto the axis of rotation of sa d'member, means on said second memberengageable with a workpiece presented thereto to'cause axial movement ofsaid second --member inwardly with respect to saidfirst member afterengagement of such means with the 5 workpiece, and means for rockingsaid support UNITED STATES PATENTS about its pivot in response torelative axial move- Number Name Date ment of said members ensuing afterengagement 1 121 326 Conner Dec 15 1914 of said first named means by thewm'kpiece- 1 435 453 Davis Jail III: Nov: 14 1922 RAYMOND LINN 1,834,716K1s Dec. 1, 1931 FOREIGN PATENTS REFERENCES CITED Number Country DateThe following references are of record in the 10 242,953 Great BritainAug. 25, 1925 file of this patent: 645,307 Germany May 25, 1937

